Steam turbine



-0. D. H. BENTLEY.

STEAM TURBINE.

APPLICATION FILED AUG. 29, l9l7.

Patented `May 9, 1922.

hiess narran stares PATENT OLIVER D. H. BENTLEY, OF ROSLINDALE, MASSACHUSETTS, ASSIGNGR TO B. E'. ST'URT'EVANT COMPANY, OF HYDE PARK, MASSACHUSETTS, A CORFGRATION l0F MASSACHUSETTS.

Specification of Letters Patent.

` STEAM TURBINE.

Tlatentedr May 9, 192,2.

To all whom t may concern:

Be it known that I, OLIVER I). I-I. BENT- LEY, a citizen of the United States residing at Roslindale, in the county of Suollr and State of Massachusetts, have invented .certain new and useful Improvements in Steam Turbines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art vto which it appertains to make and use the saine.

The present invention relates to steam turbines.

The principal objects of the present invention .are to provide a turbine which may be operated upon a low pressureof steam and at low speeds of rotation. Another object is to devise a turbine particularly adapted for small sizes and powers, which is simple in construction and cheap to manufacture. A further object is to-provide a turbine which is particularly adapted to drive a directly-connected propeller fan or analogous apparatus, the turbine being designed to develop in operation an end thrust to counterbalance the thrust of the fan or other apparatus.

With these objects in view, the present invention consists in the turbine hereinafter described and more particularly defined in the claims.

In the accompanying drawings which illustrate what is now considered a preferred embodiment of the present invention as applied to the driving of a small propeller fan, Fig. 1 is an end elevation of the turbine and fan with the cover of the turbinev casing removed; and Fig. 2 is a vertical section of the turbine on line 9.-2, Fig. 1, looking in the direction of the arrows.

In the illustrated embodiment of the present invention the turbine casing 1 comprises .a substantially cylindrical body portion 2 with inlet and exhaust passages 3 and 4, respectively, on opposite sides thereof, and provided with flanges .5 and 6. Within the body portion of the casing is formed the annular rotor chamber 7. Within this chamber and at one end thereof is the rotor 8 mounted upon the shaft 9. Steam is supplied to the rotor from the steam supply connection through the inlet passage 3 and the nozzles l() progressively arranged in a series in the outer wall of the chamber 7 and opposite the periphery of the rotor.

The rotor 8 comprises a disk or plate 11, from which project laterally the blades 12. These blades are concave on their steam receiving face and are free on their outer .and inner peripheral edges 13 and 14 respectively, and lalso on Vtheir lateral edges 15 opposite the disk. Steam passages 16 are thus formed in the rotor betweenv the adjacent blades, the inlet ports being located on the outer periphery of the rotor, while the exhaust ports are located at the side as well as on the inner peripheryof the rotor.

Not only does the provision of the lateral as well as inward discharge ports facilitate the escape of steam from the rotor but the lateral discharge of steam results in an end thrust on the turbine shaft which is utilized as hereinafter explained to counterbalance the thrust of the propeller fan. In order to increase the lateral discharge of steam vfrom the rotor the surfacer of the disk 11 from which the blades project is frusto-conical in shape, thus providinginclined yor obliquely disposed side walls 17 for'the steam passages which deliectthe steam towards 'the free ends of the blades.

As a further ,assistance in clearing the rotor of the exhaust4 steam, the inner peripheral edges 14 of the blades are made of greater axial length than the outer edges 13, thus providing a longer inner exhaust vport than inlet port. v

To allow for the lateral and inward discharge from the rotor the annular rotor chamber 7 is of a greater axial length and radial width than are the rotor blades, thus providing an exhaust space S18 adjacent the free ends of the blades and also within their l inner periphery. The exhaust steam escapes from the space 18 through the exhaust passage 4.

This exhaust passage, it will be observed, extends across the peripheral face of the rotor so that the blades, after passing the last of the nozzles 10, may then act as fan blades to draw steam from the exhaust space within the inner edges of the blades and dis- Usage 4.

charge it peripherally directly into the passage 4 The rotor is secured upon the shaft 9 at one end thereol by the taper pin 19, and at the opposite end is secured the lian 20 by a similar pin 21. rlllhe shattis mounted to turn in the bearing sleeve 22 within the bearing hub 23 and having the flange 24r engaging with the inner end of the hub. Byv

reducing the outside diameter of' this sleeve throughout its middle portion, a grease reservoir 25 is ,formed for supplying lubricant lto the shaft, the grease also serving to pack the bearing and prevent the escape of steam. A grease cup 26 supplies grease to the reservoir.

A, convenient method 'of forming the casing is to makeit in two parts, as; shown in Fig. 2. @n one part are formed the bearing hub 2?)y and the open-sided annular rotor chamber 7, the opensided inlet and exhaust passages 3 and 4, and the open-sided inlet nozzles 10, as shown in Fig. 1. This member can be cast integrally and what machining is necessary can be easily and `conven-l iently performed. rfhe other membery of they casing forms a closure for the rotorchamber, for the opensided inlet' and exhaust passages, and for the open-sided nozzles. The connecting flanges 5 and 6 are formed partly upon each member of the casing. Preferably flanges 27 are formed where the casing` is divided, screws or bolts 'passing through holes 28 in the llanges securing the two members together.

A convenient and inexpensive way of forming the rotor is to die-cast itin one piece. The design'is such that this is possible, and, owing to the low rotational speeds and small diameter or' the rotor, ample strength and rigidity are obtained.

In operation a source of low pressure steamy supply, such, for example, as the exhaust from a high pressure steam engine or turbine, having been connected to the inlet connection 5, steam flows along the inlet passage 3 and through the series of nozzles 10 and, striking against the concavefaces of the blades 12, drives the rotor in the direction indicated by the arrows. vAs the rotor turns, each blade or steam passage of the rotor receives steam from each nozzle successively, the supply thus being practically continuous for an angular rotation of about 120C?.

rll`he steam is discharged both laterally from the end edges 15 of the blades and inwardly vfrom the inner edges 14 into the exhaust space 17 from which it flows directly into the exhaust passage 4, or is drawn back into the steam passage between the blades after they have passed the last nozzle 10 to be discharged .from the outer peripheral edges 13 of the blades into the exhaust pas- By properly proportioning the rotor as to the blade and inclination of the disk between adjacent blades, the desired amount o1" end thrust will be obtained to counter-bah ance the thrust of the fan 20, thus avoiding loss of power and excessive wear.

The improved turbine above describedis of simple construction and cheap to manufacture, and it may be formed of a few cast parts which require but little machining. It is particularly adapted for operation upon a low pressure of steam as by the provision of a series oi nozzles and ample exhaust space a relatively large amount of steam may be passed through the rotor. l

lWhile the turbine illustratedinthe drawings and above described is specially designed and adapted to be operated by steam, it is to be understood that the present invention is' not limited to the use of such as motive power as the turbine may be driven by com# pressed air, gas, etc. v y Q Having thus described the present invention, what is claimed is: Y y

1. A steam turbine, having, in combination, a rotor having steam passages therein with their inlet or receiving` end portions adjacent tlie outer periphery of the rotor substantially in line with the inlet nozzles in the casing and with discharge ports at one side of the rotor, and a casing ior the rotor having a steam inlety nozzle and an exhaust opening at the outer periphery of the rotor,

nozzles in the casing and with discharge ports at one side and at the inner periphery of the rotor to discharge the steam inwardly and backwardly, and a casing for the rotor having a steam inlet nozzle and an exhaust opening at the outer periphery of the rotor,

an exhaust space at the side of the rotor and r.

an exhaust space at the side and inner pe- .l

riphery of the rotor anda wall in close proximity to the periphery of' the rotor between the nozzle and the exhaust opening.

3. A steam turbine, having, in combination, a rotor comprising a disk, blades extending from one face thereof and having their edges free. at the outer and inner peripheries and at the side opposite the disk, a casing for the rotor having an annular rotor chamber with an inlet nozzle in its outer wall andan exhaust passage, the chambe'rbeing of grater axial length than the rotor and having its inner wall spaced inwardly from the inner edges of the blades of the rotor to permit -the discharge of steam 1 blades.

4f. A steam turbine, having, in combination, a rotor hai/ing blades with free outer peripheral edges to receive the steam from the inlet Anozzle and with free lateral and inner peripheral edges to discharge the steam, the blades being oil' greater axial length on their inner than on their outer peripheral. edges, and a casing for the rotor having a steam inlet nozzle at the out-er periphery of the rotor and an exhaust passage at the side and inner periphery of the rotor.

5. A steam turbine, having, in combination, a rotor comprising a plurality of blades with free outer and inner peripheral edges and with their lateral edges free on one side and closed on the other by a wall extending inwardly from the outer edges to the hub of the rotor and with the marginal portion of said wall between said outer and inner peripheral edges inclined toward the free lateral edges of the blades, and a casing having a steam inlet opposite the outer peripheral edges of the blades and an exhaust space adjacent the inner peripheral'and lateral edges of the blades.

6. A steam turbine, having, in combination, a rotor provided with blades each having two of its edges free to permit the entrance and escape of steam and adapted to receive steam at its periphery, a casing for the rotor having a cylindrical rotor chamber provided with a series of steam inlet nozzles progressively arranged in the outer peripheral wall of the chamber, a common steam supply passage with which said nozzles are in communication, an exhaust space within the casing adjacent the free edges of the blades and an exhaust passage in the wall of the chamber located beyond the series of nozzles in the direction of rotation of the rotor and communicating with the eX- haust space.

7. A steam turbine, having, in combination, a rotor comprising a disk having a truste-conical surface adjacent its periphery, blades projecting laterally from said surface, the outer and inner peripheral edges of the blades being free and substantially parallel with the axis of rotation, a casing for the rotor having an annular chamber provided with a series ofsteam inlet openings in its outer peripheral wall, the chamber being of greater axial length and radial width than the blades of the rotor to provide an exhaust space.

8. A steam turbine, having, in combination, a casing comprising two members, vone member having formed therein an open-sided annular rotor chamber, open-sided inlet and exhaust passages, and 'an open-sided nozzle between the inlet passageand the chamber, the other member of the casing forming a closure for the side of the chamber, of the inlet and exhaust passages, and of the nozzle, means for securing the two members together, and a rotor located withinthe chamber.

9. The combination with va turbine having a casing, a shaft, and a rotor upon the shaft,

of a fan mounted upon the shaft and having blades obliquely disposed with respect to their plane of rotation, the rotor having steam passages the discharge ends of which are offset in an aXia-l direction from the inlet ends whereby the steam imparts an end thrust to the rotor shaft, the Obliquity of the fan blades and their direction of rotation being such as to impart an end thrust to the shaft opposite in direction tothat imparted by the steam.

l0. The combination with a turbine having a casing, a shaft, and a rotor upon the shaft, of a fan mounted upon the shaft and having blades obliquely disposed with respect to their plane of rotation, the rotor having steam passages with inlet ports at its periphery and discharge ports offset axially from the inlet ports, and the casing having a steam inlet opposite the periphery of the rotor and an exhaust passage, the Obliquity of the blades of the fan and their direction of rotation ybeing such relatively to the direction in which the discharge ports are offset from the inlet ports that the thrust of the fan and of the rotor are in opposite directions.

1l. A rotor for steam turbines and the like which comprises a disk integrally formed with blades projecting laterally thereupon adjacent its periphery, the edges of the blades being free except for the supporting disk and the Surface of the disk adjacent the blades and between the outer and inner extremities thereof inclined inwardly toward the free lateral edges ofthe blades.

12. The combination with ashaft of a fan thereon which develops an end thrust in operation, a steam turbine mounted upon the shaft for driving the fan comprising blades and end partitions between the blades at one end of the turbine, a nozzle for supplying steam to the blades, the end partitions being so inclined to the--direction of flow of the steam from the nozzle that the steam impinges upon the end partitions and develops an end thrust upon the turbine for counterbalancing the thrust of the fan,

13. A steam turbine having, in combination, a rotor having blades with free outer peripheral edges to receive the steam from the inlet nozzle and with free inner peripheral edges and free lateral edges on one side to discharge the steam, the blades being of greater axial length on their inner than on their outer peripheraledges, and a casing for the rotor having a steam inlet nozzle at the outer periphery of the rotor and an eX- haust passage at the free lateral edgesl and the inner peripheral edges of the blades of the rotor.

14. Amachine of' the class described havperipheral edges to receive the steam, free ing, in combination, a shaft, a 'fan mounted inner peripheral edges and free lateral edges on the shaft that develops an end thrust in on one side to discharge the steam, and a l0 operation, a steam turbine mounted on they casing for the rotor constructed to provide 5 shaft acting to develop an end thrust coun-v en exhaust space between the v:free lateral terbalencng the end thrust of the fan com: edges of the rotor and a side of the casing. prising a rotor having blades With free outei` OLIVER D. H. BENTLEY.- 

